Summary

Oral anticoagulants (OA) are the drug of choice for stroke prevention
in patients with non-rheumatic atrial fibrillation (NRAF). This clear
benefit/risk ratio comes from several randomized clinical trials (RCT)
in which highly selected patients were strictly monitored. The aim of
this study was to ascertain whether the safety of OA was also obtained
outside the setting of clinical trials in consecutive patients starting
treatment and routinely followed at Italian anticoagulation clinics.
A total of 433 patients with NRAF were enrolled in the ISCOAT study
and followed up for a mean of 1.4 years. Two patients (0.3% per year)
suffered from a complete non-fatal ischemic stroke, 8 patients (1.3% per
year) died of thrombosis-related vascular death, and 11 patients
(11 events, 1.8% per year) suffered from major bleedings (2 fatal). Major
bleeding occurred more frequently in patients >75 years of age (6 events,
5.1% per year) than in younger patients (5 events, 1.0% per year).
The cumulative incidence of major bleeding in patients over 75 years
of age (10.8%; 95% CI, 1.8-19.8) was significantly higher than in
younger patients (2.8%; 95% CI, 0.3-5.3, p = 0.006). Major primary
bleeding unrelated to organic lesions (7 patients, 1 male and 6 females)
occurred in 5 elderly patients (>75 years old) with a cumulative incidence
(9.6%; 95% CI 0.8-18.4) significantly higher than in younger
patients (1.2%; 95% CI, 0-3.0, p = 0.0003). Univariate analysis revea-led
a higher frequency of major primary bleeding in females, in diabetic
patients and in in those who had suffered a previous thromboembolic
event. Multivariate analysis revealed that only age grater than 75 years
was independently related to major primary bleedings (RR 6.6; 95% CI
1.2-37, p = 0.032). Minor bleedings (n = 27) were not more frequent in
elderly patients (6% vs 4% per year, p = ns). Patients were kept at optimal
intensity of treatment for 63% of the time. These data confirm the
efficacy of OA but identify elderly patients as a high risk group of
major bleeding.